Zyklische Bemessung von Zugstäben mit Endgewinden unter Berücksichtigung des Größeneinflusses und des Herstellungsverfahrens, IGF-Nr. 19800N
As a result of cyclic loading, the fatigue strength must be proven for the tension rods, especially for the detail of the first load bearing thread root. In steel construction, this is usually carried out according to the nominal stress concept in Eurocode 3. According to DIN EN 1993-1-9 the detail category 50 has to be used for threaded tension rods made of mild steel. A differentiation with regard to the manufacturing process of the thread is not provided.
Within the scope of the research project, the size effect up to M100, the influence of the thread manufacturing process (rolled or cut), as well as the influence of hot-dip galvanizing on the fatigue strength are investigated. Classical S-N-curves are systematically determined. By means of static and cyclic material tests, the fatigue properties of the mild steel used are investigated. These serve as input parameters for a determination of the fatigue life according to the notch strain concept. The calculated notch strains are then validated for the different thread diameters and by means of optical strain field measurements. Extensive parameter studies on size effect, manufacturing tolerances and imperfections are performed on the validated FE-model.
The database thus created will allow a clear notch case assignment for threaded tension rods made of mild steel.
Publications within the framework of the RTG
Conference contribution with publication in conference proceedings:
J. Unglaub, H. Jahns and K. Thiele. Finite Element Analysis of Residual Stresses in Large Cold-Rolled Threads. XV International Conference on Computational Plasticity - COMPLAS 2019, September 3-5, 2019, Barcelona, Spain, 2019.